"She's trying to get pregnant," O'Donnell tells Oz on The Rosie Show. (O'Donnell will also appear on Oz's daytime talk show Feb. 2)

"Michelle is seeing a fertility doctor," a source close to O'Donnell tells Us Weekly. "She is really excited and they cannot wait to add to their family. Rosie goes to all of her doctors' appointments with her and is really supportive. She isn't pregnant yet but they hope as soon as possible she will be."

Looking to tie the knot on Long Island where she grew up, O'Donnell -- who was married to Kelli Carpenter from 2004-2007 -- intends to have a low-key ceremony, and involve her four children: Blake, Parker, Chelsea and Vivienne.

"She is thinking of having her brother walk her down the aisle. She wants a proper, traditional wedding this time around," explains the source. "Michelle will say vows to the kids as well as to Rosie."

O'Donnell confirmed her engagement in December 2011 during a commercial break from The Rosie Show, telling Us later that she knew Rounds was The One "about a week after we met" at a Starbucks coffee shop. "She's literally perfection."